1. Field of the Invention
This invention relates to an electronic controller for controlling an internal combustion engine for vehicles, in particular to an electronic controller for preventing the acceleration vibration in longitudinal direction of the vehicle when the vehicle is accelerated.
2. Description of the Prior Art
FIG. 1 is a block diagram showing a general construction of an electronic controller for an internal combustion engine shown together with a schematic diagram showing a basic construction of the internal combustion engine.
One example of the conventional electronic controller for an internal combustion engine, for example an apparatus disclosed in Japanese Patent Laid-Open No. 59-96446 (1984), is first described with reference to FIG. 1.
In the drawing, reference numeral 1 designates an internal combustion engine, reference numeral 2 designating a suction pipe connected with the internal combustion engine 1, and reference numeral 3 designating a throttle valve disposed in said suction pipe 2.
A pressure within the suction pipe 2 is detected by a pressure sensor 4 and the detected pressure is transmitted to an AD converter 91. A number of revolution (engine speed) of the internal combustion engine 1 is detected by a revolution sensor 5 in the form of pulse number and an output of the revolution sensor 5 is transmitted to an input circuit 92. In addition, an injector 6 is adapted to jet a fuel into the suction pipe 2 and is driven by an output of an output circuit 96. In addition, the throttle valve 3 is provided with a throttle-opening sensor 8 for detecting an opening thereof connected therewith. An output corresponding to the throttle-opening is transmitted to the AD converter 91.
Reference numeral 11 is a distributor which is connected between ignition plugs (not shown) and an ignition coil 10. The ignition coil are driven by an output signal of an output circuit 97, so that the ignition timing of the engine 1 is controlled.
On the other hand, reference numeral 9 designates a controller for calculating a required fuel quantity from informations of the pressure sensor 4, the revolution sensor 5, the throttle-opening sensor 8 and the like and generating a driving pulse width of the injector 6. The AD converter 91 in the controller 9 converts analog signals from the throttle-opening sensor 8, the pressure sensor 4 and the like to digital values which are transmitted to a micro processor (.mu.-P) 93. The input circuit 92 level-converts the pulse output signal of the revolution sensor 5 and an output from the input circuit 92 is transmitted to the micro processor 93.
The micro processor 93 calculates a supply fuel quantity to the internal combustion engine 1 on the basis of the digital pulse signals outputted from the AD converter 91 and the input circuit 92 and determines the driving pulse width of the injector 65 correspodning to the calculated result to output it. The controlling procedure and data for the micro processor 93 are previously stored in a ROM 94 and data under the calculating process are temporarily stored in a RAM 95. And, the injector 6 is driven by means of the output circuit 96 corresponding to an output signal from the micro processor 93.
Nextly, an operation of the above described conventional apparatus is described with reference to a flow chart shown in FIG. 2.
At first, in a step 100, a pulse signal, that is, a revolution number Ne of an engine, inputted from the revolution sensor 5 is read into micro processor 93; in a step 101, a value Pb of a intake pressure (absolute pressure) in the suction pipe 2 obtained from the pressure sensor 4 is read into micro processor 93; and in a step 102, the basic driving pulse width .tau..sub.o of the injector 6 is calculated on the basis of the read-in informations.
An operational equation of above calculation is expressed by EQU .tau..sub.o =K.multidot.Pb.multidot..eta.v,
wherein K is constant; .eta.v is a charging efficiency previously determined in correspondence to the intake pressure Pb within the suction pipe 2 and the revolution number Ne of the engine 1.
Subsequently, the operation enters a step 104 periodically through a step 103, where it is judged whether a variation of quantity of the output from the throttle-opening sensor 8 exceeds the predetermined value or not. In the case where the variation of change of the output from the throttle-opening sensor 8 exceeds the predetermined value, it is judged as an accelerated condition and the operation enters a step 105, where a jetting pulse width .tau..sub.Acc corresponding to the accelerated increase in value is calculated, and then the operation enters a step 106.
Also in the case where it is judged as `No` in the step 103 and the step 104, the operation enters the step 106.
In the step 106, it is judged whether it is a fuel-jetting timing or not. In the case of the fuel-jetting timing, the jetting fuel pulse width .tau. is calculated by an equation .tau.=.tau..sub.o +.tau..sub.Acc in a step 107, and the jetting of fuel is executed in a step 108. The above described operation is repeated to control an air fuel ratio to an predetermined value.
In addition, the value of the accelerated increase operated in the step 105 is previously determined so that a torque generated in the engine may be risen by step by step and then be constant in the case where the acceleration is performed at a time t.sub.o, as shown in FIG. 3(A).
According to the conventional electronic controller for an internal combustion engine, only the output power of the engine is suddenly risen and then made constant without taking care of the generation of the vibration after the judgment of acceleration, as above described, and a problem has occurred in that an uncomfortable acceleration vibration of vehicle in longitudinal direction generated by a compound vibration system formed by connecting the engine and the vehicle, as shown in FIG. 3(B), can not be perfectly suppressed for all of various accelerating conditions.